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A movement with unexpected characteristics in terrestrial magnetism intrigues scientists around the world and it is necessary to update existing models of magnetic field description.
Because of its liquid metal core, the Earth operates as a huge magnet with positive and negative poles. The magnetic field is a "layer" of forces around the planet between these two poles.
Known as the magnetosphere, this great layer is extremely important for earthly life.
"It's the magnetic field that protects us from particles from the outside, especially the solar wind (which can be very harmful)," says geologist Ricardo Ferreira Trindade, researcher at the # 39; Institute of Astronomy and Geophysics of the University of São Paulo. (USP)
The essential magnetic field is generated by the movement of liquid metals constituting the center of the planet. As the flow varies, the field changes.
The North Pole is constantly changing its magnetic position, but still within limits.Although the direction of these changes is unpredictable, the speed was generally constant
However, in recent years, magnetic north has been moving from Canada to Siberia at a much faster rate than that predicted by scientists.
Field Model
This change forces geomagnetism scientists to to update the global magnetic model, a kind of map describing the magnetic field in space and time.
"It is created from a set of observations made in the world ent for 5 years, from which a global model that changes over time and in space, showing the variability of the field, is badembled, "explains Trindade. . "It's sort of a 4D card".
The model is important because it forms the basis of hundreds of modern navigation technologies, from ships' route controls to Google Maps.
"It's fundamental for geolocation and even satellite positioning," says the geologist.
The latest version of the model was completed in 2015 and is expected to last until 2020, but the speed with which the magnetosphere has changed has the effect of forcing scientists to update the model in advance.
In addition to pole shift, an electromagnetic pulse detected in South America in 2016 generated a change shortly after the model was updated in 2015.
The many unexpected changes have increased the number of times in the year. errors in the time of the current model. (19659002) According to Nature, researchers at Noaa (US Center for Oceanic and Atmospheric Administration) and the British Geological Survey Center realized that the model was so outdated that it was almost beyond the acceptable limit – and was about to generate possible navigation errors.
The new update is scheduled for January 30, 2019, according to Nature, one of the world's most prestigious scientific journals.
Space Security
The model is also essential for the security of the space.
Since the distribution of the field is neither homogeneous nor weaker, the protection it offers is smaller – it means that these areas, especially at very high altitudes, are a little more vulnerable to winds solar
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]" Atmospheric equipment, including satellites and telescopes, is more likely to to be damaged if they fly over these areas, "he explains.
The causes
Scientists strive to understand why the magnetic field changes so rapidly.
" The field is very variable and very unpredictable, "says geologist Marcia Ernesto, also a researcher at the Institute of Astronomy and Geophysics at the University of São Paulo (USP).
The North Pole Movement could be linked to a jet of liquid iron moving beneath the surface of the Earth's crust in the region under Canada, according to a study by researchers from the University of Leeds published in Nature Geoscience in 2017.
According to Philip W. Livermore, one of the authors of the study, it could weaken the magnetic field in Canada, while that of Siberia remains strong, which would "pull" magnetic north to Russia.
The field is so variable that the magnetic North Pole and South Pole have been inverted several times since the formation of the planet.
Its current configuration is the same as 700,000 years ago, but it can begin to reverse at any time. According to Ernesto, this reversal would take about a thousand years.
"It may be that (accelerating changes on the ground) means that one is heading for a reversal, but that is not a certainty. maybe a momentary acceleration, "says Márcia Ernesto.
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